1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a resist used for a printing method used in a patterning method for manufacturing an LCD device.
2. Discussion of the Related Art
Among various ultra-thin flat type display devices, which include a display screen having a thickness of several centimeters (cm), an LCD device may be widely used for notebook computers, monitors and aircraft due to the advantageous properties of low power consumption and portability.
The LCD device includes lower and upper substrates and a liquid crystal layer formed between the lower and upper substrates.
The lower substrate includes: gate and data lines crossing each other to define a unit pixel region; a thin film transistor switching element formed adjacent to a crossing of the gate and data lines; and a pixel electrode electrically connected to the thin film transistor.
The upper substrate includes: a black matrix layer to prevent light from leaking around the gate line, the data line and the thin film transistor; a color filter layer formed on the black matrix layer; and a common electrode formed on the color filter layer.
The LCD device includes various elements that are formed by performing processes repeatedly. In order to pattern the various elements of LCD device in various shapes, it is necessary to a use photolithography.
FIGS. 1A to 1D are cross sectional views illustrating a related art photolithography process.
First, as shown in FIG. 1A, a pattern material layer 20 and a photoresist layer 30 are sequentially formed on a first substrate 10.
Then, a mask having a predetermined pattern is positioned above the photoresist layer 30, and light is applied thereto from a light source, as shown in FIG. 1B.
Next, as shown in FIG. 1C, the pattern material layer 20 and the photoresist layer 30 are patterned by development and etching.
As shown in FIG. 1D, the photoresist layer 30 is removed by a photoresist stripper, thereby completing the pattern.
The photolithography process uses the mask with a predetermined pattern, whereby the manufacturing cost is increased because masks are expensive. Also, the manufacturing time increases and the process is complicated due to the development process.
To solve these problems in photolithography process, a new patterning method using a printing roll has been proposed.
FIGS. 2A to 2D are cross sectional views illustrating a patterning method using a printing roll according to the related art.
First, as shown in FIG. 2A, a photoresist 30 is applied onto a printing roll 60 having a blanket 65 through a printing nozzle 50, wherein the blanket 65 is adhered to the surface of printing roll 60. That is, the printing roll 60 is coated with the photoresist 30.
The blanket 65 is formed of resin that is elastic. When the photoresist 30 on printing roll 60 is transcribed on a printing plate 70, a frictional force between the printing roll 60 and the printing plate 70 is decreased due to the elasticity of the blanket 65.
Next, as shown in FIG. 2B, the printing roll 60 is rolled on the printing plate 70 having a plurality of protrusions. Thus, some of the photoresist 30 is transcribed on the protrusions of printing plate 70, and the remaining photoresist 30 forms a predetermined pattern on the printing roll 60.
As shown in FIG. 2C, the printing roll 60 is then rolled on a substrate 10 including the pattern material layer 20. Thus, the photoresist 30 is transcribed on the substrate 10 including the pattern material layer 20.
Then, as shown in FIG. 2D, the pattern material layer 20 is etched using the photoresist 30 as a mask. Then, the photoresist layer 30 is removed using a photoresist stripper, thereby completing the pattern.
The photoresist 30 may be used not only for the photolithography but also for the mask to etch the pattern material 20 in the patterning method using the printing roll 60.
The photoresist is suitable for the photolithography in that the properties of photoresist are changed by light. When using the photoresist in the patterning method using the printing roll without the exposure, a defective pattern may occur, so that it is impossible to obtain the desired pattern.
Thus, there is need for a new resist that may substitute for the photoresist in the patterning method using the printing roll.